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Mysterious Green Meteorite Lands at The Field Museum

Thursday, January 30, 2014

It looks like something out of a Superman movie – a green rock from another planet, resembling the fictional “kryptonite”. This particular rock is not fictional, however, and comes from a small planet in our solar system that has never been sampled before by scientists.

“The Field Museum is privileged to have a relationship with the renowned meteorite collector, Terry Boudreaux, who has generously donated a part of a new meteorite to our collections” said Philipp Heck, Robert A. Pritzker Associate Curator of Meteoritics and Polar Studies at The Field Museum. “It is our mission to make the samples that we receive from him accessible to the international scientific community.”

”I have been fortunate enough to pursue my passion by collecting and donating meteorites to The Field Museum and other institutions for the benefit of science,” said Terry Boudreaux, who has been collecting meteorites since 1985. “My collecting started at a fossil show, when I saw a booth with a man selling meteorites. I was amazed that I able to hold a piece of a star in my hand!”

We find meteorites on earth because some asteroids have unstable orbits, and are colliding, causing pieces to break off and enter Earth’s atmosphere. The math indicates that most fall into the sea, or uninhabited places on Earth where no one will ever find them. Even though some may land in a big city like Chicago, they might never be found, because they will be destroyed by one winter!

“This meteorite was found in Southern Morocco,” said Boudreaux. “It is rare because it is from a planet or asteroid where its particular type of chemical composition is currently unknown to scientists. It adds another piece of the puzzle to our overall understanding of the Universe and our Solar System, and how they came to be.”

When a new meteorite arrives at The Field Museum, Heck and his team spend a great deal of time studying the sample; the meteorite sometimes needs to be classified and compared to the existing database, which contains over 48,000 different meteorites. This is accomplished by polishing a section of the sample to expose the minerals, which can be analyzed under the microscope.

Most meteorites are primitive, meaning that their composition hasn’t changed since their formation. Those that are not primitive are differentiated, meaning that they have been exposed to long-term heating and pressure that has caused the metals to separate and sink to the middle of the body, forming a core – like Earth.

“The majority of meteorites have already been classified when they arrive,” said Heck. “This one was also classified, but is classified as ‘ungrouped’, because it doesn’t match anything in our database.”

Scientists can tell from this sample that whatever parent planet this meteorite came from is not primitive – it has a core, a mantel, and a crust.

Over the course of the next year or so while the meteorite is being studied, scientists can use chemical techniques to ask other questions about it, such as “How long was its journey?” and “When did the core of this planet form?”

“We are very excited about this particular meteorite, because it tells us that the other meteorites we already have represent only a fraction of all the planets that are out there,” said Heck. “The more we learn about what else is in our solar system, the better equipped we are to understand our own planet, and how best to care for it.”